[Federal Register Volume 65, Number 61 (Wednesday, March 29, 2000)]
[Notices]
[Pages 16594-16598]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-7739]
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ENVIRONMENTAL PROTECTION AGENCY
[PF-928; FRL-6498-5]
Notice of Filing Pesticide Petition to Establish Tolerance for
Certain Pesticide Chemicals in or on Food
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice.
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SUMMARY: This notice announces the intial filing of a pesticide
petition proposing the establishment of regulations for residues of
certain pesticide chemicals in or on various food commodities.
DATES: Comments, identified by docket control number PF-928, must be
received on or before April 28, 2000.
ADDRESS: Comments may be submitted by mail, electronically, or in
person. Please follow the detailed instructions for each method as
provided in Unit I.C. of the SUPPLEMENTARY INFORMATION. To ensure
proper receipt by EPA, it is imperative that you identify docket
control number PF-928 in the subject line on the first page of your
response.
FOR FURTHER INFORMATION CONTACT: By mail: James A. Tompkins,
Registration Division (7505C), Office of Pesticide Programs,
Environmental Protection Agency, Ariel Rios Bldg., 1200 Pennsylvania
Ave., NW., Washington, DC 20460; telephone number: (703) 305-5697; e-
mail address: [email protected].
SUPPLEMENTARY INFORMATION:
I. General Information
A. Does this Action Apply to Me?
You may be affected by this action if you are an agricultural
producer, food manufacturer or pesticide manufacturer. Potentially
affected categories and entities may include, but are not limited to:
------------------------------------------------------------------------
Examples of
Categories NAICS potentially
affected entities
------------------------------------------------------------------------
Industry 111 Crop production
112 Animal production
311 Food manufacturing
32532 Pesticide
manufacturing
------------------------------------------------------------------------
This listing is not intended to be exhaustive, but rather provides
a guide for readers regarding entities likely to be affected by this
action. Other types of entities not listed in the table could also be
affected. The North American Industrial Classification System (NAICS)
codes have been provided to assist you and others in determining
whether or not this action might apply to certain entities. If you have
questions regarding the applicability of this action to a particular
entity, consult the person listed under FOR FURTHER INFORMATION
CONTACT.
B. How Can I get Additional Information, Including Copies of this
Document and Other Related Documents?
1. Electronically. You may obtain electronic copies of this
document, and certain other related documents that might be available
electronically, from the EPA internet Home Page at http://www.epa.gov/.
To access this document, on the Home Page select ``Laws and
Regulations'' and then look up the entry for this document under the
``Federal Register--Environmental Documents.'' You can also go directly
to the Federal Register listings at http://www.epa.gov/fedrgstr/.
2. In person. The Agency has established an official record for
this action under docket control number PF-928. The official record
consists of the documents specifically referenced in this action, any
public comments received during an applicable comment period, and other
information related to this action, including any information claimed
as confidential business information (CBI). This official record
includes the documents that are physically located in the docket, as
well as the documents that are referenced in those documents. The
public version of the official record, does not include any information
claimed as CBI. The public version of the official record, which
includes printed, paper versions of any electronic comments submitted
during an applicable comment period, is available for inspection in the
Public Information and Records Integrity Branch (PIRIB), Rm. 119,
Crystal Mall #2, 1921 Jefferson Davis Highway, Arlington, VA, from 8:30
a.m. to 4 p.m.,
[[Page 16595]]
Monday through Friday, excluding legal holidays. The PIRIB telephone
number is (703) 305-5805.
C. How and to Whom Do I Submit Comments?
You may submit comments through the mail, in person, or
electronically. To ensure proper receipt by EPA, it is imperative that
you identify docket control number PF-928 in the subject line on the
first page of your response.
1. By mail. Submit your comments to: Public Information and Records
Integrity Branch (PIRIB), Information Resources and Services Division
(7502C), Office of Pesticide Programs (OPP), Environmental Protection
Agency, Ariel Rios Bldg., 1200 Pennsylvania Ave., NW., Washington, DC
20460.
2. In person or by courier. Deliver your comments to: Public
Information and Records Integrity Branch (PIRIB), Information Resources
and Services Division (7502C), Office of Pesticide Programs (OPP),
Environmental Protection Agency, Rm. 119, Crystal Mall #2, 1921
Jefferson Davis Highway, Arlington, VA. The PIRIB is open from 8:30
a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The
PIRIB telephone number is (703) 305-5805.
3. Electronically. You may submit your comments electronically by
e-mail to: ``[email protected],'' or you can submit a computer disk as
described above. Do not submit any information electronically that you
consider to be CBI. Avoid the use of special characters and any form of
encryption. Electronic submissions will be accepted in Wordperfect 6.1/
8.0 or ASCII file format. All comments in electronic form must be
identified by docket control number PF-928. Electronic comments may
also be filed online at many Federal Depository Libraries.
D. How Should I Handle CBI That I Want to Submit to the Agency?
Do not submit any information electronically that you consider to
be CBI. You may claim information that you submit to EPA in response to
this document as CBI by marking any part or all of that information as
CBI. Information so marked will not be disclosed except in accordance
with procedures set forth in 40 CFR part 2. In addition to one complete
version of the comment that includes any information claimed as CBI, a
copy of the comment that does not contain the information claimed as
CBI must be submitted for inclusion in the public version of the
official record. Information not marked confidential wil be included in
the public version of the official record without prior notice. If you
have any questions about CBI or the procedures for claiming CBI, please
consult the person identified under FOR FURTHER INFORMATION CONTACT.
E. What Should I Consider as I Prepare My Comments for EPA?
You may find the following suggestions helpful for preparing your
comments:
1. Explain your views as clearly as possible.
2. Describe any assumptions that you used.
3. Provide copies of any technical information and/or data you used
that support your views.
4. If you estimate potential burden or costs, explain how you
arrived at the estimate that you provide.
5. Provide specific examples to illustrate your concerns.
6. Make sure to submit your comments by the deadline in this
notice.
7. To ensure proper receipt by EPA, be sure to identify the docket
control number assigned to this action in the subject line on the first
page of your response. You may also provide the name, date, and Federal
Register citation.
II. What Action is the Agency Taking?
EPA has received a pesticide petition as follows proposing the
establishment and/or amendment of regulations for residues of certain
pesticide chemicals in or on various food commodities under section 408
of the Federal Food, Drug, and Comestic Act (FFDCA), 21 U.S.C. 346a.
EPA has determined that this petition contains data or information
regarding the elements set forth in section 408(d)(2); however, EPA has
not fully evaluated the sufficiency of the submitted data at this time
or whether the data supports granting of the petition. Additional data
may be needed before EPA rules on the petition.
List of Subjects
Environmental protection, Agricultural commodities, Feed
additivies, Food additives, Pesticides and pests, Reporting and
recordkeeping requirements.
Dated: March 24, 2000
James Jones
Director, Registration Division, Office of Pesticide Programs.
American Cyanamid Company
0F6088
Summary of Petition
EPA has received a pesticide petition (0F6088) from American
Cyanamid Company, P.O. Box 400, Princeton, NJ 08543-0400 proposing,
pursuant to section 408(d) of the Federal Food, Drug, and Cosmetic Act
(FFDCA), 21 U.S.C. 346a(d), to amend 40 CFR part 180 by establishing a
tolerance for residues of the herbicide imazamox in or on the raw
agricultural commodities alfalfa forage, seed and hay, canola seed,
legume vegetable crop group and wheat forage, grain, bran, shorts, hay
and straw at 2.0, 0.1, 4.0, 0.1, 0.1, 0.4, 0.3, 0.6, 0.6, 0.3, and 0.2
parts per million (ppm), respectively. EPA has determined that the
petition contains data or information regarding the elements set forth
in section 408(d)(2) of the FFDCA; however, EPA has not fully evaluated
the sufficiency of the submitted data at this time or whether the data
support granting of the petition. Additional data may be needed before
EPA rules on the petition.
A. Residue Chemistry
1. Plant metabolism . The qualitative nature of the residues of
imazamox (AC 299263) in soybeans, alfalfa, canola, peas, and wheat is
adequately understood. The metabolism of imazamox has been studied in
soybeans, peas, and canola. EPA has concluded that the nature of the
residue is adequately understood and the residues of concern are the
parent imazamox only. The metabolism of imazamox was also studied in
wheat. EPA has concluded that the nature of the residue is adequately
understood and the residues of concern are the parent imazamox, and the
desmethyl, hydroxy-methyl metabolite CL 263284. The metabolism of
imazamox was further studied in alfalfa. EPA has concluded that the
nature of the residue is adequately understood and the residues of
concern are the parent imazamox, metabolite CL 263284, the carboxylate
of the CL 263284 metabolite, CL 312622 and the glucoside of the CL
263284 metabolite, CL 189215.
2. Analytical method. A practical analytical method for detecting
and measuring levels of imazamox in soybean seed was submitted to and
approved by EPA. This method (M 2248.01) is appropriate for enforcement
purposes. A practical analytical method
[[Page 16596]]
for detecting and measuring levels of imazamox in canola seed was
submitted to EPA. This method (M 3076) is appropriate for enforcement
purposes. A practical analytical method for detecting and measuring
levels of imazamox in legume vegetables (such as dry and succulent
edible beans and peas) was submitted to EPA. This method (M 3076 with
minor modifications) is appropriate for enforcement purposes. A
practical analytical method for detecting and measuring levels of
imazamox and its metabolite CL 263284 in wheat grain, forage, hay and
straw was submitted to EPA. This method (M 3098) is appropriate for
enforcement purposes. A practical analytical method for detecting and
measuring levels of imazamox and its metabolites: CL 263284, its (CL
263284) glucose conjugate (CL 189215), and the carboxylate of AC 263284
(CL 312622) in alfalfa seed, forage and hay was submitted to EPA. This
method (M 3178) is appropriate for enforcement purposes. All methods
have undergone independent laboratory validation as required by PR
Notices 88-5 and 96-1.
3. Magnitude of residues--i. Magnitude of residues in crops--a.
Soybeans, legume, vegetables and canola: No apparent residues of
imazamox were observed in soybeans, dry or succulent peas, or dry or
succulent beans, or canola at or above 0.05 ppm (the limit of
quantification for the analytical methods). The field studies,
conducted at 1- 5x the highest intended label use rate, clearly support
the proposed tolerances of 0.1 ppm. The requirement for a soybean
processing study was waived by EPA based on the results of field trials
at rates up to 5x the maximum label rate. In these trials, there was no
measurable residue of imazamox in soybean seed above the validated
sensitivity of the method (0.05 ppm). In addition, results from the
plant metabolism study showed no detectable residues of imazamox in oil
obtained from soybean seed that had been treated at an exaggerated use
rate.
b. Wheat. A total of 20 field residue trials were conducted in 10
different states. Applications in the trials were consistent with the
proposed label directions for use. Analysis of the treated samples
showed that the maximum imazamox plus its metabolite CL 253284 was
under the proposed tolerances of 0.3 ppm in the grain, 0.4 ppm in the
forage, 0.3 ppm in the hay and 0.2 ppm in straw at the proposed labeled
pre-harvest intervals (PHI). Wheat grain for processing was obtained
from a 5x-rate field study and samples were processed into bran,
middling, shorts, flour and aspirated grain fractions. Analysis of the
treated samples showed that the total residue of the imazamox parent
and the metabolite CL 263284 concentrated in bran and shorts. The
appropriate concentration factor for bran and shorts is 2x. The
proposed tolerance for these two fractions is at 2x the tolerance for
the proposed grain tolerance of 0.3 ppm or 0.6 ppm.
c. Alfalfa. A total of 19 field residue trials were conducted in 12
different states. Applications in the trials were consistent with the
proposed label directions for use. Analysis of the treated samples
showed that the maximum residues of imazamox plus its three metabolites
(CL 263284, CL 263284 glucose conjugate metabolite CL 189215, and CL
263284 carboxylate, CL312622) were under the proposed tolerances of 0.1
ppm in the seed, 2.0 ppm in the forage and 4.0 ppm in the hay at the
proposed labeled (PHI)
ii. Magnitude of the residue in animals--a. Ruminants. The maximum
dietary burden in beef and dairy cows results from a diet comprised of
alfalfa hay and alfalfa forage for a total dietary burden that is
significantly lower than levels that would require the proposal of
tolerances in ruminants. This conclusion is based on exaggerated rate
metabolism studies carried out on imazamox and its significant
metabolites. Therefore, an exemption from tolerances in milk, meat and
meat by-products under 40 CFR 180.6(a)(3) and (b) is proposed as it is
not possible to establish with certainty whether finite residues will
be incurred, but there is no reasonable expectation of finite residues.
d. Poultry. The maximum poultry dietary burden results from a diet
composed of alfalfa hay (meal) and wheat grain for a total dietary
burden that is significantly lower than the levels that would require
the proposal of tolerances in poultry. This conclusion is based on the
exaggerated rate metabolism studies carried out on imazamox and its
significant metabolites. Therefore, an exemption from tolerances in
poultry meat, meat by-products, fat and eggs under 40 CFR 180.6(a)(3)
and (b) is proposed as it is not possible to establish with certainty
whether finite residues will be incurred, but there is no reasonable
expectation of finite residues.
B. Toxicological Profile
A complete battery of mammalian toxicity studies supports the
tolerances for imazamox on soybeans and the rest of the legume
vegetable crop grouping, canola, wheat and alfalfa. The data base is
complete, valid and reliable, and all studies have been submitted to
and approved by EPA. The toxicological data submitted to support the
subject petition as amended include:
1. Acute toxicity. Imazamox technical is considered to be nontoxic
(Toxicity Category IV) to the rat by the oral route of exposure. In the
acute oral toxicity study in rats, the LD50 value of
imazamox technical was greater than 5,000 milligrams/kilograms body
weight (mg/kg bwt) for males and females. The results from the acute
dermal toxicity study in rabbits indicate that imazamox is slightly
toxic (Toxicity Category III) to rabbits by the dermal route of
exposure. The dermal LD50 value of imazamox technical was
greater than 4,000 mg/kg bwt for both male and female rabbits. Imazamox
technical is considered to be nontoxic (Toxicity Category IV) to the
rat by the respiratory route of exposure. The 4-hour LC50
value was greater than 6.3 mg/L (analytical) for both males and
females. Imazamox technical was shown to be non-irritating to slightly
irritating to rabbit skin (Toxicity Category IV). Based on the results
of a dermal sensitization study (Buehler), imazamox technical is not
considered a sensitizer in guinea pigs.
2. Genotoxicty. Imazamox technical was tested in the following four
assays measuring several different endpoints of potential genotoxicity.
Collective results from these studies indicate that imazamox does not
pose a mutagenic or genotoxic risk.
i. Bacterial Mutagenicity assay - Negative.
ii. In vitro structural chromosomal aberration assay - Negative.
iii. In vitro CHO/HGPRT assay - Negative.
iv. In vivo micronucleus aberration assay - Negative.
3. Reproductive and developmental toxicity. The development
toxicity study in rats conducted with imazamox technical showed no
evidence of teratogenic effects in fetuses and no evidence of
developmental toxicity. Thus, imazamox is neither a developmental
toxicant nor a teratogen in the rat. The results from this study
supported a no observed adverse effect level (NOAEL) for developmental
toxicity of 1,000 mg/kg bwt day, the highest dose tested and limit
dose. The NOAEL for maternal toxicity was 500 mg/kg bwt day, based on
reduced mean body weights, weight gains and food consumption at 1,000
mg/kg bwt day. Results from a developmental toxicity study in rabbits
conducted with imazamox technical also indicated no evidence of
teratogenicity or developmental toxicity. Thus, imazamox technical is
neither a developmental toxicant nor a teratogen
[[Page 16597]]
in the rabbit. In the rabbit developmental toxicity study, the NOAEL
for maternal toxicity was 300 mg/kg bwt day, based on decreased food
consumption at 600 mg/kg bwt day, the next highest dose tested. The
NOAEL for developmental toxicity was 900 mg/kg bwt day, the highest
dose tested. The results from the two-generation reproduction toxicity
study in rats with imazamox technical support a NOAEL for parental and
reproductive toxicity of 20,000 ppm (or approximately 1,639 mg/kg bwt
day, calculated from the food consumption data), the highest
concentration tested. The NOAEL for growth and development of offspring
is also 20,000 ppm (or approximately 1,639 mg/kg bwt day. Results from
the reproduction study and the developmental toxicity studies conducted
with imazamox technical show no increased sensitivity to developing
offspring as compared to parental animals, because the NOAELs for
growth and development of offspring were equal to or greater than the
NOAELs for parental or maternal toxicity.
4. Subchronic toxicity. No treatment-related adverse effects were
noted in subchronic toxicity studies at the highest doses tested. A
short-term (28-day) dermal study in rabbits was conducted with imazamox
technical. No dermal irritation or systemic toxicity was observed at
dose levels up to and including 1,000 mg/kg bwt day (highest dose
tested), supporting a NOAEL of 1,000 mg/kg bwt day. In a subchronic
(13-week) dietary toxicity study in rats with imazamox technical, no
signs of systemic toxicity were noted, supporting a NOAEL of 20,000 ppm
(or approximately 1,661 mg/kg bwt day, calculated from food consumption
data), the highest concentration tested. In a subchronic (90-day)
dietary toxicity study in dogs with imazamox technical, no signs of
systemic toxicity were noted, supporting a NOAEL of 40,000 ppm (or
approximately 1,368 mg/kg bwt day, calculated from the food consumption
data), the highest concentration tested.
5. Chronic toxicity. The low order of mammalian toxicity of
imazamox technical is also evident from the chronic dietary toxicity
studies. These studies showed no increased mortalities or clinical
signs of toxicity attributed to imazamox treatment. Moreover, there
were no treatment-related effects on food consumption, body weights,
organ weights, or hematology, clinical chemistry, urinalysis or
ophthalmologic parameters. There was no gross or microscopic evidence
of treatment-related lesions or carcinogenicity in the three chronic
studies conducted in dogs, mice, or rats.
A 1-year dietary study was conducted with imazamox technical in
dogs at dietary concentrations of 0, 1,000, 10,000, and 40,000 ppm. The
NOAEL for this study was 40,000 ppm (or approximately 1,165 mg/kg bwt
day, based on food consumption), the highest concentration tested.
A chronic feeding/carcinogenicity study was conducted with imazamox
technical in male and female rats at dietary concentrations of 0,
1,000, 10,000, and 20,000 ppm. The NOAEL for systemic toxicity and
carcinogenicity was 20,000 ppm (or approximately 1,167 mg/kg bwt day,
based on food consumption) the highest concentration tested.
A chronic feeding/carcinogenicity study was conducted with imazamox
technical in male and female mice at dietary concentration of 500,
3,500, and 7,000 ppm. The NOAEL for systemic toxicity and
carcinogenicity was 7,000 ppm (or approximately 1,201 mg/kg bwt day,
based on food consumption), the highest concentration tested.
In the dietary exposure analysis for AC 299263 in/on Soybeans (PP
6F4649) dated March 24, 1997, EPA determined that AC 299263 cancer
classification is classified as not likely (to induce tumors in humans)
according to the proposed new guidelines.
6. Animal metabolism. The qualitative nature of the residues of
imazamox and its metabolites CL 263284 and CL 263284 carboxylate CL
312622 in animals is adequately understood. Based on metabolism studies
with goats, hens and rats, there is no reasonable expectation that
measurable imazamox-related residues will occur in meat, milk, poultry
or eggs from the proposed use.
7. Metabolite toxicology. No toxicologically significant
metabolites were detected in plant or animal metabolism studies for
soybeans or the rest of the crops in the legume vegetable crop
grouping: (6) or canola. Therefore, no metabolites need to be regulated
in these crops.
The plant metabolism study in wheat indicated very low residues of
concern. A very small amount of the metabolite CL 263284 was found in
the wheat grain.
The plant metabolism in alfalfa indicated very low residues in the
alfalfa seed. However, the parent imazamox underwent metabolism to the
metabolite CL 263284 (the same metabolite seen in wheat). This
metabolite was captured by a glucose molecule to form the glucose
conjugate CL 189215 and the hydroxymethyl AC 263284 was also further
oxidized to the carboxylate metabolite CL 312622.
Both metabolites, CL 263284 and CL 312622 were present in the rat
metabolism study.
No additional toxicologically significant metabolites were detected
in any plant or animal studies.
8. Endocrine disruption. Collective organ weight data and
histopathological findings from the two-generation rat reproductive
study, as well as from the sub-chronic and chronic toxicity studies
conducted in two or more animal species, demonstrate no apparent
estrogenic effects or effects on the endocrine system. There is no
information available that suggests that imazamox would be associated
with endocrine effects.
C. Aggregate Exposure
1. Dietary exposure. The potential dietary exposure to imazamox has
been calculated from the proposed tolerances for use on soybeans and
other members of the legume vegetables crop grouping (6), canola, wheat
and alfalfa. These very conservative chronic dietary exposure estimates
used the tolerance value for all the raw agricultural commodities. In
addition these estimates assume that 100% of the crops contain imazamox
residues.
i. Food. The Theoretical Maximum Residue Concentrations (TMRC) of
imazamox on or in soybeans and other members of the legume vegetable
crop grouping (6), canola, alfalfa, wheat grain, and its processed
fractions are; 0.00577 mg/kg bwt day for the general U.S. population;
0.000573 mg/kg bwt day for non-nursing infants; 0.001306 mg/kg bwt day
for children 1 to 6 years of age; and 0.000887 mg/kg bwt day for
children 7 to 12 years of age.
ii. Drinking water. As a screening level assessment for aggregate
exposure, EPA evaluates Drinking Water Level of Comparison (DWLOC),
which is the maximum concentration of a chemical in drinking water that
would be acceptable in light of total aggregate exposure to that
chemical. Based on the chronic reference dose (RfD) of 3.0 mg/kg bwt
day, determined by EPA, and the EPA's default factors for body weight
and drinking water consumption, the DWLOCs have been calculated to
assess the potential dietary exposure from residues of imazamox in
water. For the adult population, the chronic DWLOC was 104,980 parts
per billion (ppb), and for children, the DWLOC was estimated to be
29,987 ppb.
Chronic drinking water exposure analyses were calculated using EPA
screening models (SCI-GROW for ground, water and GENEEC for surface
[[Page 16598]]
water). The calculated peak GENEEC value is 0.44 ppb and the SCI-GROW
value is 0.055 ppb. For the U.S. adult population, the estimated
exposures of imazamox residues in surface water and ground, water are
approximately 0.0004% and 0.00005%, respectively, of the DWLOC. For
children, the estimated exposures of imazamox residues in surface water
and ground water are approximately 0.002% and 0.0002%, respectively of
the DWLOC. Therefore, the exposures to drinking water from imazamox use
are negligible.
Based on the dietary and drinking water assessments, aggregate
exposure to residues of imazamox in food and water can be considered to
be negligible.
2. Non-dietary exposure. There is no available information
quantifying non-dietary exposure to imazamox. However, based on the
physical and chemical characteristics of the compound, the proposed use
pattern and available information concerning its environmental fate,
non-dietary exposure is not expected.
D. Cumulative Effects
Imazamox belongs to the imidazolinone class of compounds. The
herbicidal activity of the imidazolinones is due to the inhibition of
acetohydroxy acid synthase (AHAS), an enzyme only found in plants. AHAS
is part of the biosynthetic pathway leading to the formation of
branched chain amino acids. Animals lack AHAS and this biosynthetic
pathway. This lack of AHAS contributes to the extremely low toxicity of
imazamox in mammals. Although other registered imidazolinones have a
similar herbicidal mode of action, there is no information available to
suggest that these compounds exhibit a similar toxicity profile in the
mammalian system. We are aware of no information to indicate or suggest
that imazamox has any toxic effects on mammals that would be cumulative
with those of any other chemical. Since imazamox is relatively non-
toxic, cumulative effects of residues of imazamox and other compounds
are not anticipated. Therefore, for the purposes of this tolerance
petition no assumption has been made with regard to cumulative exposure
with other compounds having a common mode of herbicidal action.
E. Safety Determination
1. U.S. population. Based on a RfD of 3.0 mg/kg bwt day determined
from a NOAEL of 300 mg/kg bwt day, from the rabbit developmental
toxicity study and a safety (uncertainty) factor of 100, the worse case
estimate of chronic dietary exposure of imazamox from soybeans, the
other members of the legume vegetable crop grouping (6), canola, wheat
and alfalfa will utilize approximately 0.02% of the RfD for the general
U.S. population. EPA generally has no concern for exposures below 100%
of the RfD because the RfD represents the level at or below which daily
aggregate dietary exposure over a lifetime will not pose appreciable
risks to human health. The complete and reliable toxicity data and the
conservative chronic exposure assumptions support the conclusion that
there is a reasonable certainty of no harm from dietary (food) exposure
to imazamox residues. Moreover, as exposure to residues of imazamox via
water is negligible, there is a reasonable certainty of no harm from
aggregate exposure to imazamox residues.
2. Infants and children. The conservative estimates, as described
above, indicate that dietary exposure of imazamox from soybeans, the
other members of the legume vegetable crop grouping, canola, wheat and
alfalfa will utilize: approximately 0.02% of the RfD for non-nursing
infants; approximately 0.04% of the RfD for children ages 1 to 6; and
approximately 0.03% of the RfD for children ages 7 to 12.
No developmental, reproductive, or fetotoxic effects were noted at
the highest doses of imazamox tested in guideline reproductive or
developmental toxicity studies. The only maternal effects in the rat
and rabbit teratology studies were decreased body weights, body weight
gains and/or absolute and relative feed consumption in the higher dose
groups of each study.
Based on the current toxicological data requirements, the data base
relative to prenatal and postnatal effects for children is complete,
valid and reliable. Results from the teratology studies and the two-
generation reproduction study support NOAELs for fetal/developmental
effects or reproductive/offspring effects, respectively, equivalent to
the highest concentrations tested. As such, there is no increased
sensitivity of infants and children to residues of imazamox. Therefore,
an additional safety (uncertainty) factor is not warranted, and the RfD
of 3.0 mg/kg bwt day, which utilizes a 100-fold safety factor, is
appropriate to assure a reasonable certainty of no harm to infants and
children.
F. International Tolerances
There is no Codex Maximum Residue Level Established for Residues of
Imazamox on any Crops.
[FR Doc. 00-7739 Filed 3-28-00; 8:45 am]
BILLING CODE 6560-50-F